[anchor] Search inclusive ancestors for the anchor-scoping element
We incorrectly used exclusive ancestors, making it impossible to anchor
against elements that both name and scope some anchor name.
Fixed: 373815812
Change-Id: I5eaab2f38589f02470c5229573c199f1b3715424
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5938970
Commit-Queue: Anders Hartvoll Ruud andruud@chromium.org
Reviewed-by: Rune Lillesveen futhark@chromium.org
Cr-Commit-Position: refs/heads/main@{#1370556}